Safety toe iron for ski bindings



Sept. 3, 1968 G. ADAM 3,399,902

SAFETY TOE IRON FOR SKI BINDINGS Filed Feb. 16, 1967 5 Sheets-Sheet 1 11 faV//// 11 7- 4" T Sept. 3, 1968 G. ADAM 3,399,902

SAFETY TOE IRON FOR SKI BINDINGS Filed Feb. 16, 1967 5 Sheets-Sheet 2 FIG. 3

Sept. 3, 1968 G. ADAM 3,399,902

SAFETY TOE IRON FOR SKI BINDINGS Filed Feb. 16, 1967 3 Sheets-Sheet 3 United States Patent 3,399,902 SAFETY TOE IRON FOR SKI BINDINGS Giinter Adam, Thorlenstrasse 43, Garmisch- Partenkirchen, Germany Filed Feb. 16, 1967, Ser. No. 616,710 Claims priority, application Germany, Feb. 24, 1966, M 68,519 4 Claims. (Cl. 28011.35)

ABSTRACT OF THE DISCLOSURE A safety toe iron for ski bindings comprises a main pivoted member, which is pivoted to the ski, and a sole holder member, which is engageable by the forward edge of the sole of the skiing boot under the action of a tightener on the heel of the boot. One of these two members carries two pivot pins, which are equally spaced on opposite sides of its longitudinal center line. The other of these two members is formed with two guide slots, which are respectively engaged by said pivot pins and extend each along an arc of a circle, which is centered on the rear end of the respective other guide slot, if the slots are formed in the sole holder, or on the forward end of the respective other guide slot if the slots are formed in the main pivoted member. The arrangement is such that the pivot pins engage the rear ends of said slots in the normal position of the toe iron.

It has recently been required to provide ski bindings with safety toe irons which in response to harmless lateral impacts and slight torsional stresses permit of a small outward pivotal movement of the foot and then return the foot to the central position whereas these toe irons releases the foot only in response to substantial forces which are dangerous to the foot of the skier. This requirement has been met by various known designs. In one case, a piston-like restoring member extends horizontally in the pivoted member of the toe iron and is urged by a strong coil spring against a fiat of the pivot pin for the pivoted member. Upon any pivotal movement of the pivoted member, the restoring member is urged back by one of the edges of the flat and under the action of the coil spring tends to return to its initial position so that the pivoted member is returned to its normal position. These known safety toe irons may consist of double-pivot assemblies, in which a sole holder is pivoted to the main pivoted member. Alternatively, the pivoted member itself may be formed with the surface for engaging the forward edge of the sole of the boot so that the release causes the forward edge of the sole of the boot to roll along the abutment surface of the pivoted member. In the first case, the tightener, which bears on the heel directly or by a wire cable, applies pressure to the boot immediately after the beginning of the pivotal movement and pushes the boot forwardly in unison with the forward movement of the sole holder. For this reason, the coil spring, which acts by means of the piston member against the flat of the pivot pin, can effect a return movement only if the spring overcomes the force of the tightener, which acts in the longitudinal direction of the ski. This is possible only after relatively small pivotal movements of the foot, which cannot result in a considerable forward displacement. For this reason, the foot held by the known binding may come to rest in a dead-center position, from which it cannot be returned against the tightener pressure by the force of the spring which is contained in the pivoted member, and, on the other hand, the foot is not released in said position. When the foot is in such dead-center position, a fall of the skier is almost inevitable.

In the other known safety toe iron, a pivotal movement of the foot and the pivoted member is also possible to "ice such an extent that the foot will be neither restored nor released because the tightener has moved the foot forwardly during the outward pivotal movement of the foot and because the frictional forces also oppose a satisfactory restoring movement. Another disadvantage of the two known bindings resides in that there is always an intermediate zone between the angular range in which pivotal movements are elastically damped by a steadily increasing resistance, and the angular range in which the foot is released. The restoring force of the spring remains virtually constant in that intermediate zone. For this reason, said known binding does not meet the requirement that the foot should be instantaneously released when the torque force which is still tolerable by the foot is exceeded. Besides, the known binding involves relatively high manufacturing costs because there is only a very small leverage for the force of the coil spring so that the same must be relatively strong.

Further known suggestions to solve the problem set forth differ in details of construction from the known toe iron binding which has been discussed above but have the same disadvantages so that they are not specifically discussed here.

It is an object of the invention to provide a safety toe iron which is intended for use in ski bindings and elastically takes up the forces which act on the foot in the case of slight impacts and subsequently returns the foot to its central position, whereas the foot is instantaneously released when the permissible torque is exceeded. The safety toe iron should be designed so that the force exerted by the tightener in the longitudinal direction of the ski is utilized for restoring the foot to its normal position after an action of slight forces so that no separate spring means are required which are adjustable to the limiting torque which is tolerable by the foot. This concept results in a safety toe iron which has no adjusting elements so that it can be manufactured at particularly low cost.

To solve the objects set forth above, the invention provides a known double-pivot safety toe iron for ski bindings, which toe iron comprises a main pivoted member, which is rotatable about a pivot pin that is at right angles to the surface of the ski, and a sole holder, which is pivoted to the main pivoted member and has a vertical abutment surface, against which the forward edge of the sole of the skiing boot bears with a wide surface, as the boot is elastically urged forwardly by a tightener. In response even to a slight deflection of the main pivoted member from its normal position, the sole holder will be pivotally moved in the opposite direction and will be immediately moved forwardly so that the tightener is relieved. If the main pivoted member is locked to the surface of the ski by a usual ball detent mechanism, the tightener acting in the longitudinal direction of the ski will contribute to the further outward pivotal movement of the safety toe iron immediately when the detent ball has been released from the detent socket so that the boot is released very quickly. For this reason, such an arrangement cannot effect an elastic restoring action in response to slight lateral impacts. As has already been stated, this has been observed even when there is no ball detent device which cooperates with the surface of the ski, or with a baseplate secured to said surface, but the known spring-loaded piston mechanism is adopted. In this case there is also the problem that the spring which biases the piston acts with a very small leverage and must overcome the force of the tightener in order to restore the main pivoted member and with it the boot.

In a double-pivot safety toe iron of the kind defined above, the object of the invention is accomplished in that the sole holder is pivoted to the main pivoted member by two vertical pivot pins, which are spaced on opposite sides from the longitudinal center line of the main pivoted member and engages respective guide slots formed in the sole holder in accordance with arcs of a circle, each of which arcs is centered on the forward end of the other guide slot, the rear end faces of the guide slots engaging the pivot pins in the normal position. In the arrangement according to the invention, the sole holder urges the boot rearwardly to some extent against the action of the tightener during an outward pivotal movement of the main pivoted member because that of the eccentric pivot pin which is trailing in the direction of the outward pivotal movement is then constrained to perform a movement along an arc of a circle which has a component that is rearwardly directed in the longitudinal direction of the ski. As this pivot pin bears on the rear end of its guide slot, the sole holder cannot yield, but must urge the boot rearwardly. It will depend on the eccentricity of the pivot pins to what extent the boot must be urged to the rear until a release is effected, which takes place when the pivot pin which is trailing in the direction of the outward pivotal movement has traversed the longitudinal center line of the ski. Thus, only the adjustment of the tightener, which acts in the longitudinal direction of the ski and forces the skiing boot against the toe iron, will determine the magnitude of the force which will cause a release of the skiing boot. This adjustment will also determine the magnitude of the forces which move the boot to a position from which it is subsequently restored because the tightener force which acts in the longitudinal direction of the ski tends to urge the toe iron back to its normal position as long as the pivot pin which is trailing in the direction of the outward pivotal movement has not traversed the longitudinal center line of the ski. The angle through which the main pivoted member must be moved until the pivot pin which is trailing in the direction of the outward pivotal movements has traversed the longitudinal center line of the ski is thus the range from which an elastic restoring action takes place after the occurrence of relatively small lateral impacts and torsional stresses. The foot is not released unless it is acted upon by a force which is so strong or has continued for such a long time that the pivot pin which is trailing in the direction of the outward pivotal movement has traversed the longitudinal center line of the ski so that the boot is no longer urged to the rear by the sole holder. During the pivotal movement, the pivot pin which is leading in the direction of the outward pivotal movement slides in its guide slot because the pivot pin which is leading in the direction of the outward pivotal movement is not significant for the specific function of the toe iron according to the invention. The guide slot which guides said leading pivot pin extends along an arc of a circle about the point where the pivot pin which is trailing in the direction of the outward pivotal movement is then disposed so that the relative movement between the pivot pin which is leading in the direction of the outward pivotal movement and its guide slot is not obstruced.

In another embodiment of the invention, the sole holder is mounted by two vertical pivot pins, which are eccentrically secured to the sole holder on both sides of the longitudinal center line of the sole holder, and the pivot pins extend into respective guide slots formed in the main pivoted member, each of said guide slots forming a portion of an arc of a circle centered on the forward end of the respective other guide slot and the pivot pins engaging the forward end faces of the guide slots in the normal position. This is an inversion of the embodiment in which the pivot pins are provided on the main pivoted member and the guide slots are formed in the sole holder.

In a development of the invention, means may be provided for elastically holding the main pivoted member and/or the sole holder in the normal position. These means are not significant for the releasing function of the toe iron and serve only to facilitate the stepping into the toe iron without need for holding the toe iron by hand while the foot is stepping into the binding.

Two illustrative embodiments of the safety toe iron according to the invention will be described more fully hereinafter with reference to the drawing, in which FIG. 1 is a sectional view taken on line II of FIG. 2 and showing a safety toe iron according to the invention,

FIG. 2 is a horizontal sectional view taken on line II-II of FIG. 1,

FIG. 3 is a view similar to FIG. 2 and shows the toe iron according to the first embodiment during the releasing operation,

FIG. 4 is a view similar to FIG. 1 and shows a second embodiment in a sectional view taken on line IV-IV of FIG. 5,

FIG. 5 is a top plan view showing the embodiment of FIG. 4.

The first embodiment of a safety toe iron according to the invention is shown in FIGS. 1 to 3 and comprises a base plate 3, which is secured to a ski 1 by screws 2 and carries a screw-threaded pivot pin 4 for mounting the toe iron. A main pivoted member 5 has a tapped bore 6 and is rotatably mounted on the pivot pin 4. By one or more revolutions of the main pivoted member 5 about the pivot pin 4, the main pivoted member can be adjusted in height when a stop screw 7 has been removed. This screw serves to prevent an unintended adjustment in height.

The forward edge of the sole of the boot is engageable with a sole holder 8, which forms a wide-mouthed sole holder and entirely embraces the forward edge of the sole of the boot. The forward edge of the sole of the boot bears on a vertical abutment surface 9 of the sole holder 8. A flange 10 of the sole holder prevents a lifting of the boot from the ski. In the known double-pivot safety toe irons, the sole holder is pivoted to the main pivoted member by a pivot pin, which is disposed in the longitudinal center line of the main pivoted member so that an outward pivotal movement of the main pivoted member will impart to the sole holder from the beginning a movement which has a forwardly directed component. According to the invention, the pivoted member is provided with two eccentric pivot pins 11, 12, which are spaced from its longitudinal center line and extend into guide slots 13, 14 formed in the sole holder 8. Each of the guide slots 13, 14 is formed in accordance with an arc of a circle, which is centered on the rear end of the opposite guide slot or on the left-hand end thereof as viewed in the drawing. As is apparent from FIG. 1, each pivot pin 11, 12 extends .from above entirely through the main pivoted member 5 so that a stable mounting is ensured.

The skiing boot, not shown in the drawing, is elastically forced against the sole holder 8 by a tightener, which acts on the heel of the boot. In the normal position, the rear ends of the guide slots 13, 14, or the left-hand ends thereof as viewed in the drawing, bear on the pivot pins 11, 12, which are secured to the main pivoted member 5. In this way, the main pivoted member is reliably held in its central position without need for a detent device or another retaining device for this purpose.

When a lateral force or a torque U is acting on the skiing boot which is held in the sole holder 8, the boot will tend to yield laterally and will take the sole holder 8 along. During this movement, the pivot pin which is trailing in the direction of the outward pivotal movement, in the showing of FIG. 3 the pivot pin 11, remains in engagement with the rear end of the guide slot 13 whereas the pivot pin 12 is displaced in the guide slot 14 because the sole holder remains in engagement with the forward edge of the sole of the boot. It is clearly apparent from FIG. 3 that the pin 1], which is trailing in the direction of the outward pivotal movement, describes during this movement an arc of a circle, which is centered on the axis of the pivot pin 4. The pin 11 will then urge the sole holder 8 rearwardly or to the left in the drawing to a small extent until the pin 11 has traversed the longitudinal center line of the ski.

The forward thrust exerted by the tightener opposes the rearward component of the movement of the pivot pin 11 which is trailing in the direction of the outward pivotal movement. This thrust tends to restore the pin 11 and with it the entire toe iron to its normal position, in which both pivot pins 11, 12 engage the rear ends of the guide slots 13, 14. The larger the force to which the tightener is adjusted, the larger is also the force which causes the pivot pin 11, which is trailing in the direction of the outward pivotal movement, to urge back the boot against the action of the tightener to such an extent that the pivot pin 11 traverses the longitudinal center line of the ski. The pivot pin will subsequently move forwardly to enable a rapid further outward pivotal movement of the toe iron. Hence, lateral impacts are elastically clamped in an increasing degree until the pivot pin 11 which is trailing in the direction of the outward pivotal movement has reached its rearmost position. This damping is effected by the forward thrust of the tightener and does not require any elastic means in the toe iron itself. If the acting lateral or torsional force is sufficient to move the trailing pivot pin 11 beyond its rearmost position, the foot will be instantaneously released. The main pivoted member 5 must then be swung back by hand approximately to its central position to enable the foot to step again into the binding. When the forward edge 'of the sole of the boot has engaged the abutment surface 9 and the tightener is applied, the safety toe iron will be immediately moved definitely to its normal position.

In the embodiment shown in FIGS. 4 and 5, like reference characters as in FIGS. 1 to 3 are used for like parts. The description of these parts need not be repeated. The embodiment differs from the embodiment first described in that pivot pins 15, 16 are secured to the sole holder 8 rather than to the main pivoted member 5 and guide slots 17, 18 are formed in the main pivoted member 5. In th normal position of the toe iron, the pivot pins 15, 16 engage the forward ends of the guide slots 17, 18. A screw 19 holds a weak torsion spring 20, which automatically swings the sole holder 8 back to its initial position when the foot has been released. This torsion spring has no function during the release because it is too weak to exert any appreciable force on the foot. A leaf spring 21 is secured by the stop screw 7 to the forward end of the baseplate 3. As is particularly apparent from FiG. 5, the leaf spring 21 embraces the forward end of the pivoted member 5 in its normal position so that the main pivoted member 5 is held in this position and need not be moved to and held in the central position when the skier desires to step into the binding. It will be understood that a torsion spring could be provided which cOrresponds to the spring 20 and returns the main pivoted member 5 elastically to its central position after a fall.

The safety toe iron according to the invention =comprises no adjusting means for adjusting the above-mentioned force which is required for a release because this required force depends only on the adjustment of the tightener acting on the heel. When it is desired to provide different types of safety toe irons according to the invention in order to obtain different release characteristics, the spacing of the pivot pins 11, 12 or 15, 16 and of the guide slots associated with them may be varied because the rearward movement of the pivot pin which is trailing in the direction of the outward pivotal movement will be the smaller the smaller is the spacing of this pivot pin from the longitudinal center line of the ski when this pin is in its normal position.

What is claimed is:

1. A double-pivot safety toe iron for ski bindings, comprising a pivot pin mounted at right angles to the surface of a ski, a main pivoted member rotatably mounted about said pivot pin, a sole holder having a vertical abutment surface against which the forward edge of the sole of a skiing boot bears with a wide surface as the boot is elastically urged forwardly by a tightener, and means pivotally mounting the sole holder to the main pivoted member including two vertical pivot pins which are spaced on opposite sides from the longitudinai centerline of the main pivoted member and engage respective guide slots formed in the sole holder in accordance with arcs of a circle, each said arc centered on the rear end of the other guide slot, the rear end faces of the guide slots engaging the pivot pins in the normal position.

2. A double-pivot safety toe iron for ski bindings, comprising a pivot pin mounted at right angles to the surface of a ski, a main pivoted member rotatably mounted about said pivot pin, a sole holder having a vertical abutment surface against which the forward edge of the sole of the skiing boot bears with a wide surface as the boot is elastically urged forwardly by a tightener, and means pivotally mounting the sole holder including two vertical pivot pins which are eccentrically secured to the sole holder on both sides of the longitudinal centerline of the sole holder, said pivot pins extending into respective guide slots formed in the main pivoted member, each of said guide slots forming a portion of an arc of a circle centered on the forward end of the respective other guide slot, and the pivot pins engaging the forward end faces of the guide slots in the normal position.

3. A safety toe iron according to claim 1, characterized by means for resiliently holding one of the main pivoted member .and the sole holder in a rest position.

4. A double-pivot safety toe iron for ski bindings, comprising a pivot pin mounted at right angles to the surface of a ski, a main pivoted member rotatably mounted about said pivot pin, a sole holder having a vertical abutment surface against which the forward edge of the sole of a skiing boot bears with a wide surface as the boot is elastically urged forwardly by a tightener, and means pivotally mounting the sole holder to the main pivoted member including two vertical pivot pins which are spaced on opposite sides from the longitudinal centerline of the main pivoted member and engage respective guide slots formed in the sole holder in accordance with arcs of a circle, each said are centered on the rear end of the other guide slot.

References Cited UNITED STATES PATENTS 3,079,164 2/1963 De Place 28011.35 3,107,101 10/1963 Ramillon 280-1135 3,288,477 11/ 1966 Beyl 2801 1.35

BENJAMIN HERSH, Primary Examiner.

L. D. MORRIS, Assistant Examiner. 

